Extinct Kangaroo Ancestor Wasn't Much Of a Hopper

Some ancient, extinct species of kangaroo were not equipped to bounce about like modern kangaroos do. (Photo : Flickr: Kyle Taylor)

Kangaroos are known for their spring-loaded feet, but not all of their ancient relatives were good hoppers. Researchers from the University of Queensland recently discovered a new genus and two new species of extinct kangaroos that were built to walk rather than bounce.

"They lived around 15-23 million years ago and were the size of very small wallabies or pademelons," Kaylene Butler, lead author from UQ's School of Earth Sciences, said in a news release. "They moved on all fours, scurrying across a densely forested landscape quite different from the dry outback we see in western Queensland today."

The ancient specimens were unearthed from a fossil site known as the Riversleigh World Heritage Area in north-western Queensland, Australia. Based on their findings, researchers suggest the animals are likely the ancestors of all modern kangaroos and wallabies.

"It also appears that our new species were direct competitors with a second group of kangaroos at Riversleigh, the even weirder 'balbarid' or fanged kangaroos," Butler added in the university's release. "It seems likely that the fanged cousins were out-competed by our new species and their descendants."

It is believed that the two new species -- Cookeroo bulwidarri and Cookeroo hortusensis -- were able to adapt more readily as the landscape changed from rainforest to more open forest and woodland environments.

After measuring the fossil specimens and comparing them to the skulls and teeth of other known species, researchers confirmed they had discovered a new genus, which was subsequently dubbed Cookeroo, in honor of Dr. Bernard Cooke, who is a distinguished Queensland Museum researcher that has studied the evolution of Riversleigh's ancient kangaroos.